12 results about "Common noise" patented technology

The invention discloses a combined preprocessing and fusion decoding method based on electroencephalogram signals and functional near-infrared signals, which comprises the following steps of: synchronously acquiring the electroencephalogram signals and the functional near-infrared signals, taking a task trigger event as a unified time reference, and carrying out basic preprocessing of time alignment and modal self-adaption on two modal signals to obtain a functional near-infrared signal; a pre-trained cross-modal noise joint modeling module is utilized to perform joint modeling on cross-modal joint noise features caused by a common noise source, collaborative denoising processing is performed on multi-modal signals based on the cross-modal joint noise features, multi-modal denoising representation is obtained, a cross-modal feature interactive modeling mode based on an attention mechanism is obtained, and the multi-modal noise is obtained. And dynamically modeling the correlation between different modal features, realizing deep fusion of multi-modal complementary information, carrying out decoding processing based on the fused features, and outputting a corresponding brain-computer interface control instruction or task identification result. According to the method, the decoding accuracy and robustness of the brain-computer interface system in a complex task scene are enhanced.

The invention relates to a high and steep slope real-time monitoring method and system based on multi-source data fusion and cooperative enhancement. The method comprises the following steps: scanning a slope provided with a corner reflector array by using a synthetic aperture radar (SAR); performing real-time differential correction on data acquired by the radar by taking the corner reflector in the stable region as a reference so as to eliminate common noise; meanwhile, a three-dimensional laser scanner is used for obtaining point cloud data of the slope; coordinate registration and fusion of radar data and point cloud data are realized through the corner reflector array, so that a three-dimensional deformation field of the slope is generated. The method provided by the invention has the advantages of high monitoring precision, high signal-to-noise ratio and good data reliability.

The invention discloses a synthetic aperture radiometer darkroom phase calibration method and device. The method comprises the following steps: installing a synthetic aperture radiometer and a point target emission source in a microwave anechoic chamber; in the first-stage test, unit antenna output ports are connected with equal-length test cables and connected to a microwave test instrument, a synthetic aperture radiometer is set to be in an antenna observation mode, and a point target observation unit antenna phase difference test is carried out; in the second-stage test, the output end of the unit antenna is connected with each receiving channel of the synthetic aperture radiometer, the synthetic aperture radiometer is set to be in an antenna observation mode, and a point target observation full-system phase difference test is carried out; in the third stage of testing, the synthetic aperture radiometer is set to be in a common noise injection calibration mode, and common noise injection calibration is carried out; and calculating and counteracting a near field effect phase difference, a unit antenna phase difference and a receiver channel phase difference to obtain an accurate noise distribution network phase difference parameter. Darkroom phase calibration is achieved under the near-field condition, the result is accurate, and the method is simple, convenient and practical.

The invention belongs to the technical field of geological exploration, and particularly discloses a symmetrical excitation anti-explosion geological exploration system and method, and the method comprises the steps: receiving array multi-channel signals at two sides, and carrying out the time alignment correction of all channel signals, so as to eliminate the time delay; a multi-channel cross-correlation matrix between the left array and the right array is constructed based on the aligned signals, and matrix elements are obtained through integral cross-correlation operation of array channel signals on the two sides; performing low-rank decomposition on the cross-correlation matrix, and extracting the first k main components as public noise modes; carrying out inversion calculation on the contribution of each noise mode in each acquisition channel, and reconstructing a channel noise component; and subtracting the reconstructed noise component from the original signal, and outputting a purified geological reflection signal. The method does not need special hardware, can accurately suppress the homologous low-frequency noise of the tunnel, improves the signal-to-noise ratio of the signal and the geological imaging resolution, and is suitable for geological detection of closed spaces such as the tunnel.

This invention provides a single-phase three-wire grid-connected inverter circuit that can suppress common noise more effectively than conventional circuits. [Solution] A single-phase three-wire inverter circuit comprising: a voltage divider circuit comprising two capacitors, with the neutral AC side connection terminal connected between the two capacitors; a first leg comprising two switching elements, connected to the first AC side connection terminal via a first inductor between the two switching elements; a second leg comprising two switching elements, connected to the second AC side connection terminal via a second inductor between the two switching elements; and a third leg comprising two sets of two switching elements, each with a diode facing in opposite directions, connected to the neutral AC side terminal via a third inductor between the two sets of switching elements, passing through the midpoint of the voltage divider path.

The invention relates to an atom interferometer with a laser light source through which first laser light can be emitted at a fundamental frequency, and with at least one light emission device through which second laser light can be emitted at a frequency that deviates from the fundamental frequency by a difference frequency, and with an atom trap in which one or more atom ensembles can be captured and irradiated with the first and the second laser light.

This invention provides a single-phase three-wire grid-connected inverter circuit that can suppress common noise more effectively than conventional circuits. [Solution] A single-phase three-wire inverter circuit comprising: a first leg corresponding to the first phase AC side terminal, comprising two switching elements and connected to a first inductor midway between the two switching elements; a second leg corresponding to the second phase AC side terminal, comprising two switching elements and connected to a second inductor midway between the two switching elements; and a third leg corresponding to the AC side terminal related to the neutral wire, comprising two sets of two switching elements each equipped with a diode facing in opposite directions and connected to the neutral wire AC side terminal midway between the two sets of switching elements.

This invention relates to the field of wind turbine technology and specifically discloses a noise reduction device for a wind turbine. It includes a fixed circular plate, a curved baffle fixedly connected to one side of the fixed circular plate, a circular sleeve plate fixedly connected to the side of the curved baffle away from the fixed circular plate, and a concave sound-absorbing cotton fixedly connected to the side of the fixed circular plate near the curved baffle. This noise reduction device for a wind turbine, by setting multiple curved baffles around the outside of the generator assembly to block and reduce noise, prevents the common noise-reducing shell from only sequentially blocking and intercepting noise waves, resulting in poor noise reduction and still causing a certain degree of noise. By setting the curved baffles with a zigzag shape around the outside of the generator assembly to block noise while facilitating air circulation, it prevents the sound-absorbing shell from completely enclosing the wind turbine in a sealed state, which would lead to low heat dissipation efficiency and be difficult to manage during long-term operation.

The invention relates to an atom interferometer with a laser light source through which first laser light can be emitted at a fundamental frequency, and with at least one light emission device through which second laser light can be emitted at a frequency that deviates from the fundamental frequency by a difference frequency, and with an atom trap in which one or more atom ensembles can be captured and irradiated with the first and the second laser light.

The utility model relates to the technical field of oxygenerator devices, in particular to an efficient noise-reduction oxygenerator which comprises an outer shell, a turning cover is assembled at the upper end of the outer shell, an air inlet is formed in the surface of one side of the outer shell, a base plate is assembled at the bottom of the outer shell, an air filter box is assembled on the inner side of the air inlet, and a sound absorption plate is installed at the rear end of the air filter box. The upper end and the lower end of the sound absorption plate are provided with the sound absorption side plates, the rear end of the air filter box is connected with the compressor, the rear side of the compressor is provided with the input pipeline, and the rear end of the input pipeline is provided with the molecular sieve adsorption tower. In addition, a closed environment made of sound absorption materials is assembled at each structure in the device, and a sound absorption layer arranged on the inner surface is matched, so that the interior generated can be greatly reduced, the generation of noise is effectively prevented, the device is more useful than a common noise reduction mode, and the interior of the device can be protected.

This invention discloses a method and system for synergistically improving the key performance of dynamic measurement of fiber optic current transformers, including: constructing a first mathematical model of forward channel gain and step response rise time; constructing a second mathematical model of forward channel gain and overshoot; constructing a third mathematical model of common noise and signal-to-noise ratio of the fiber optic current transformer system; based on the first and second mathematical models, with forward channel gain as the independent variable and minimizing overshoot and step response as the objectives, performing dual-objective optimization to determine the optimal forward channel gain, thereby minimizing the dynamic measurement performance (overshoot and step time) of the system; using the forward channel gain value obtained from the optimization as a constraint, improving the third mathematical model with the objective of maximizing it; and guiding the design of fiber optic current transformers based on the optimization results, which can effectively ensure that the fiber optic current transformer has good dynamic measurement performance while having a high signal-to-noise ratio, thus improving the measurement performance of the fiber optic current transformer.

The invention provides a double-spectrum iris image intelligent recognition method and system based on multi-stage characteristics, and relates to the technical field of iris image recognized.The method comprises the steps that firstly, a clear sclera boundary provided by a visible light image is used for guiding precise segmentation of a near-infrared image, and high-precision initial characteristic positioning is completed; according to the method, standard local binary features are extracted, a weight map capable of quantifying the spectral stability of each local area is generated by analyzing the difference of co-occurrence matrixes in the double-spectrum gradient direction, then collaborative filtering is carried out on the double-spectrum features in a frequency domain, non-common noise is removed, and the spectral stability of each local area is quantified. The method comprises the following steps: firstly, carrying out self-adaptive weighted fusion in a spatial domain by using a weight map to generate a highly robust composite feature, and finally, carrying out weighted Hamming distance calculation by multiplexing a spectrum stability weight map in an identification matching stage, so that the matching process focuses on a reliable feature region with high spectrum consistency. And the accuracy of the iris recognition system in the complex imaging environment is improved.